Electric toothbrushes sometimes use rechargeable batteries or accumulators accommodated within the housing of a handpiece of the toothbrush. For recharging the batteries in the handpiece, sometimes inductive chargers are used so as to avoid the problems going along with mechanical electric connectors and use thereof in wet and humid conditions. To allow inductive charging, the handpiece may include a secondary coil extending around a charging recess which may be provided in the bottom part of the toothbrush handpiece so as to be pushed onto a thorn-like or mandrel-like charger projection. Such charger projection may be provided on a top surface side of a base part and, aside from charging, may serve as a holding element for holding and storing the toothbrush handpiece in a substantially upright position. Such charger projection of the base part may include a portion of a magnetic core which cooperates with a charger coil in the base part so as to bundle and transfer the magnetic flux to the secondary coil provided in the toothbrush handpiece when said handpiece is set atop the base part with the secondary coil neighboring the magnetic core of the base part's charger coil.
When using such charger devices for charging rechargeable batteries in the handpiece of a hand-held appliance such as a toothbrush, the space available for inserting the charger projection of the inductive charger into the charging recess of the handpiece is rather limited since the outer dimensions of the handpiece are determined by ergonomic requirements since the handpiece should in particular be easily and comfortably grippable. In particular, when it is desired to provide the charging recess in the bottom part of the handpiece, the available space and the possible diameter of such recess is rather limited what may result in rather slim and small charger projections not allowing for transfer of as much energy as may be desirable. Nevertheless, so as to allow for acceptable charging times, rather large and bulky charger coils and corresponding supply equipment are used so as to be able to provide the necessary magnetic flux. The charging efficiency is limited due to undesired energy dissipation and losses.